TikTok makers ByteDance had to rush for fixing serious security issues in the TikTok app. Specifically, they addressed multiple vulnerabilities in TikTok that could expose users’ private data to hackers.
TikTok Vulnerabilities That Could Expose Data
Researchers from Checkpoint have come up with another interesting study explaining some more TikTok vulnerabilities. Exploiting these vulnerabilities could allow an adversary to steal the private data of TikTok users.
As revealed, the issues existed because of how TikTok allowed contact syncing. TikTok doesn’t necessarily require its users to include a phone number. However, if a user has associated a phone number with the app and allows contact sync, the app would then help the user connect with other TikTok users in their contacts.
Every time the app would launch, it registers the users’ devices to check for device switching. This process involves sending a HTTP request to the server which then generates a unique device_id token necessarily needed for all API requests.
If the device has enabled login with SMS, then again, the server generates an X-Tt-Token token and session cookies in response to the HTTP request. These cookies and tokens would expire after 60 days.
Hence, it became possible for an adversary to capture the HTTP requests and then collect and create a database of device IDs and contact numbers.
Though, TikTok prevented any tampering of requests the researchers could bypass the mechanism. As explained in their technical write-up
A threat actor can use a dynamic analysis framework, such as Frida, hook the function, change the data the function arguments (the contacts the threat actor wishes to sync), and re-sign the request.
Therefore, a threat actor can use this service to sign his modified requests, create an updated X-Gorgon and X-Khronos header values (message signatures) and send the modified request to the TikTok application server.
Thus, they could easily modify the HTTP requests, re-sign them, and could then create the users’ database.
TikTok Deployed Patches
Upon discovering the vulnerabilities, the researchers responsibly disclosed the bugs to TikTok.
The vendors have since fixed the vulnerabilities. Users are safe from potential exploitation of these bugs providing they are using the latest version of the app.